Those of us who come from the film world learned to do as much in camera as possible, especially when doing commercial work which was shot on transparencies. Transparency film (slides) is much harder to manipulate than when you are printing. Each new generation (when you reshoot a transparency with an added effect) added some deterioration to the overall quality. I did a lot of those, with what would be called extreme PP today, for my personal (art) work and I spent a lot of time figuring out how to add several effects at the same time to minimize the number of generations.
In the age of digital, the problem is totally different. Special effects that can be added post shoot should be added post shoot because there is no loss of quality if done correctly. This is exactly the same as in a audio recording studio (I was a recording engineer for a while.) When you start recording you lay down tracks of pure sound. The instrument as it is. Then you add the effects. If they don't fit your vision, the original pure track is still there and you can try in another direction until you get what you want.
Now, there are always exceptions to every rule. When Jimmy Page plays the guitar with a bow, that effect cannot be reproduced later (or we'll agree to assume that for the sake of the argument) so you record it from the start. In photography it would be the same with a polarizing filter. There is no way to reproduce the effect of a CPL through any of the PP software so you will use it on camera.
Now, I still do a lot in camera. I frame correctly from the start and I cringe every time I read some one saying shoot wide and crop later... In my studio, there is a shop because for some of the stuff I shoot we build some fairly involved sets. Some of those could be created on the computer and we could then insert the person or object that is the reason for the photo into it but, from my try-outs with my PP person (who is very good I might add,) it just doesn't look real enough.
Just a couple days ago there was an article about Cokin, I believe, being in trouble financially. Should we be surprised? Not really. Most of their filters' effects can be reproduced in PP and there is no reason to carry around or use most of them anymore.
Hope that helps.